peter
/
cond-values
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

cond-values: add with example

This commit is contained in:
Peter McGoron 2024-10-18 12:43:01 -04:00
commit e52009c0a2
4 changed files with 622 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

202
COPYING Normal file
View File

@ -0,0 +1,202 @@
Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
"License" shall mean the terms and conditions for use, reproduction,
and distribution as defined by Sections 1 through 9 of this document.
"Licensor" shall mean the copyright owner or entity authorized by
the copyright owner that is granting the License.
"Legal Entity" shall mean the union of the acting entity and all
other entities that control, are controlled by, or are under common
control with that entity. For the purposes of this definition,
"control" means (i) the power, direct or indirect, to cause the
direction or management of such entity, whether by contract or
otherwise, or (ii) ownership of fifty percent (50%) or more of the
outstanding shares, or (iii) beneficial ownership of such entity.
"You" (or "Your") shall mean an individual or Legal Entity
exercising permissions granted by this License.
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
Object form, made available under the License, as indicated by a
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
"Derivative Works" shall mean any work, whether in Source or Object
form, that is based on (or derived from) the Work and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship. For the purposes
of this License, Derivative Works shall not include works that remain
separable from, or merely link (or bind by name) to the interfaces of,
the Work and Derivative Works thereof.
"Contribution" shall mean any work of authorship, including
the original version of the Work and any modifications or additions
to that Work or Derivative Works thereof, that is intentionally
submitted to Licensor for inclusion in the Work by the copyright owner
or by an individual or Legal Entity authorized to submit on behalf of
the copyright owner. For the purposes of this definition, "submitted"
means any form of electronic, verbal, or written communication sent
to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems,
and issue tracking systems that are managed by, or on behalf of, the
Licensor for the purpose of discussing and improving the Work, but
excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
"Contributor" shall mean Licensor and any individual or Legal Entity
on behalf of whom a Contribution has been received by Licensor and
subsequently incorporated within the Work.
2. Grant of Copyright License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
copyright license to reproduce, prepare Derivative Works of,
publicly display, publicly perform, sublicense, and distribute the
Work and such Derivative Works in Source or Object form.
3. Grant of Patent License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
where such license applies only to those patent claims licensable
by such Contributor that are necessarily infringed by their
Contribution(s) alone or by combination of their Contribution(s)
with the Work to which such Contribution(s) was submitted. If You
institute patent litigation against any entity (including a
cross-claim or counterclaim in a lawsuit) alleging that the Work
or a Contribution incorporated within the Work constitutes direct
or contributory patent infringement, then any patent licenses
granted to You under this License for that Work shall terminate
as of the date such litigation is filed.
4. Redistribution. You may reproduce and distribute copies of the
Work or Derivative Works thereof in any medium, with or without
modifications, and in Source or Object form, provided that You
meet the following conditions:
(a) You must give any other recipients of the Work or
Derivative Works a copy of this License; and
(b) You must cause any modified files to carry prominent notices
stating that You changed the files; and
(c) You must retain, in the Source form of any Derivative Works
that You distribute, all copyright, patent, trademark, and
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
include a readable copy of the attribution notices contained
within such NOTICE file, excluding those notices that do not
pertain to any part of the Derivative Works, in at least one
of the following places: within a NOTICE text file distributed
as part of the Derivative Works; within the Source form or
documentation, if provided along with the Derivative Works; or,
within a display generated by the Derivative Works, if and
wherever such third-party notices normally appear. The contents
of the NOTICE file are for informational purposes only and
do not modify the License. You may add Your own attribution
notices within Derivative Works that You distribute, alongside
or as an addendum to the NOTICE text from the Work, provided
that such additional attribution notices cannot be construed
as modifying the License.
You may add Your own copyright statement to Your modifications and
may provide additional or different license terms and conditions
for use, reproduction, or distribution of Your modifications, or
for any such Derivative Works as a whole, provided Your use,
reproduction, and distribution of the Work otherwise complies with
the conditions stated in this License.
5. Submission of Contributions. Unless You explicitly state otherwise,
any Contribution intentionally submitted for inclusion in the Work
by You to the Licensor shall be under the terms and conditions of
this License, without any additional terms or conditions.
Notwithstanding the above, nothing herein shall supersede or modify
the terms of any separate license agreement you may have executed
with Licensor regarding such Contributions.
6. Trademarks. This License does not grant permission to use the trade
names, trademarks, service marks, or product names of the Licensor,
except as required for reasonable and customary use in describing the
origin of the Work and reproducing the content of the NOTICE file.
7. Disclaimer of Warranty. Unless required by applicable law or
agreed to in writing, Licensor provides the Work (and each
Contributor provides its Contributions) on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties or conditions
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
risks associated with Your exercise of permissions under this License.
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
result of this License or out of the use or inability to use the
Work (including but not limited to damages for loss of goodwill,
work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses), even if such Contributor
has been advised of the possibility of such damages.
9. Accepting Warranty or Additional Liability. While redistributing
the Work or Derivative Works thereof, You may choose to offer,
and charge a fee for, acceptance of support, warranty, indemnity,
or other liability obligations and/or rights consistent with this
License. However, in accepting such obligations, You may act only
on Your own behalf and on Your sole responsibility, not on behalf
of any other Contributor, and only if You agree to indemnify,
defend, and hold each Contributor harmless for any liability
incurred by, or claims asserted against, such Contributor by reason
of your accepting any such warranty or additional liability.
END OF TERMS AND CONDITIONS
APPENDIX: How to apply the Apache License to your work.
To apply the Apache License to your work, attach the following
boilerplate notice, with the fields enclosed by brackets "[]"
replaced with your own identifying information. (Don't include
the brackets!) The text should be enclosed in the appropriate
comment syntax for the file format. We also recommend that a
file or class name and description of purpose be included on the
same "printed page" as the copyright notice for easier
identification within third-party archives.
Copyright [yyyy] [name of copyright owner]
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

187
cond-values.scm Normal file
View File

@ -0,0 +1,187 @@
;;; Copyright 2024 Peter McGoron
;;; Licensed under the Apache License, Version 2.0 (the "License");
;;; you may not use this file except in compliance with the License.
;;; You may obtain a copy of the License at
;;;
;;; http://www.apache.org/licenses/LICENSE-2.0
;;;
;;; Unless required by applicable law or agreed to in writing, software
;;; distributed under the License is distributed on an "AS IS" BASIS,
;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
;;; implied. See the License for the specific language governing
;;; permissions and limitations under the License.
(import srfi-1)
;;; AFTER executes a body after multiple tests.
;;;
;;; The form of the syntax is
;;; (AFTER (BINDING ...) BODY ...)
;;;
;;; where BODY ... is a Scheme body. Each BINDING is evaluated in order,
;;; where BINDING is
;;;
;;; (VALUE => FORMAL): FORMAL is a LAMBDA formal and VALUE is a something
;;; that returns multiple values. If VALUE evaluates to no values, the
;;; test fails and the entire AFTER form returns no values.
;;;
;;; (WHEN TEST): Evaluates TEST. If TEST is #F then the entire AFTER form
;;; returns no values.
;;;
;;; If all BINDINGs pass, then BODY is executed and its return value is
;;; the return of AFTER.
(define-syntax after
(syntax-rules (when let =>)
((after ((let value => formal) conditionals ...) body ...)
(call-with-values (lambda () value)
(lambda returned
(if (null? returned)
(values)
(apply (lambda formal (after (conditionals ...) body ...))
returned)))))
((after ((let formal value ...) conditionals ...) body ...)
(after ((let (begin value ...) => formal) conditionals ...)
body ...))
((after ((when boolean) conditionals ...) body ...)
(if boolean
(after (conditionals ...) body ...)
(values)))
((after () body ...)
(begin body ...))))
(define-syntax apply-after
(syntax-rules ()
((apply-after value receiver)
(after ((let value => formal))
(apply receiver formal)))))
;;; (COND-VALUES CLAUSE ...) is like COND, but it tests for empty VALUES
;;; instead of #F.
;;;
;;; Each CLAUSE is:
;;;
;;; (BODY ...): Executes BODY. If BODY returns no values, then try the
;;; rest of the clauses. If BODY returns values, those values are the
;;; return values of COND-VALUES.
;;; (ELSE BODY ...): Must occur at the end. Executes BODY and returns
;;; whatever BODY returns.
;;;
;;; If there is no ELSE clause and all CLAUSEs fail, COND-VALUES returns
;;; no values.
(define-syntax cond-values
(syntax-rules (else)
((cond-values (else body ...))
(begin body ...))
((cond-values value rest ...)
(call-with-values (lambda () value)
(lambda returned
(if (null? returned)
(cond-values rest ...)
(apply values returned)))))
((cond-values) (values))))
;;; (DEFINE-RECORD-TYPE/DESTRUCTOR TYPENAME
;;; (CSTR FIELDS ...)
;;; PREDICATE?
;;; DESTRUCTOR
;;; (FIELD GETTER SETTER ...)
;;; ...)
;;;
;;; creates an SRFI-9/R7RS record type. The syntax is the same, except
;;; that after the PREDICATE field and before the getter/setter fields
;;; is an identifier, DESTRUCTOR.
;;;
;;; This macro defines a procedure (DESTRUCTOR RECORD) that returns each
;;; field of RECORD as values, or no values if RECORD is not a TYPENAME
;;; record.
(define-syntax define-record-type/destructor
(syntax-rules ()
((define-record-type/destructor typename
(cstr fields ...)
predicate?
destructor
(field getter setter ...)
...)
(begin
(define-record-type typename
(cstr fields ...)
predicate?
(field getter setter ...)
...)
(define (destructor record)
(after ((when (predicate? record)))
(values (getter record) ...)))))))
;;; ;;;;;;;;;;;;;
;;; Helper functions
;;; ;;;;;;;;;;;;;
;;; Returns the CAR and CDR of X as values when X is a pair, and no values
;;; otherwise.
(define (pair-d x)
(after ((when (pair? x)))
(values (car x) (cdr x))))
(define (assq-d val alist)
(let ((pair (assq val alist)))
(after ((when (pair? pair)))
(cdr pair))))
;;; Returns the list as values when WHOLE-LIST has length NUM, and no
;;; values otherwise.
(define (length* whole-list num)
(when (<= num 0)
(error "invalid number" 'length* whole-list num))
(let length* ((lst whole-list)
(num num))
(cond-values
(after ((when (null? lst))
(when (= num 0)))
(apply values whole-list))
(after ((when (pair? lst))
(when (> num 0)))
(length* (cdr lst) (- num 1))))))
;;; Returns the list as values when WHOLE-LIST has at least length NUM,
;;; and no values otherwise.
(define (length-at-least whole-list num)
(when (<= num 0)
(error "invalid number" 'length-at-least whole-list num))
(let length-at-least ((lst whole-list)
(num num))
(cond-values
(after ((when (= num 0))
(when (or (null? lst)
(pair? lst))))
(apply values whole-list))
(after ((when (> num 0))
(when (pair? lst)))
(length-at-least (cdr lst) (- num 1))))))
;;; Helper function.
(define (null-cdr? lst) (null? (cdr lst)))
;;; MAP-VALUES returns (VALUES L1 L2 ...), where L1 is the first
;;; value returned from (F (CAR LST)), (F (CADR LST)), ... and so on.
(define (map-values f . lists)
(define (null-cdr? lst) (null? (cdr lst)))
(let-values ((new-values (apply f (map car lists))))
(if (any null-cdr? lists)
(apply values (map list new-values))
(let-values ((returned (apply map-values f (map cdr lists))))
(apply values (map cons new-values returned))))))
;;; (ANY-VALUES F (A1 A2 ...) (B1 B2 ...) ...) runs
;;; (F A1 B1 ...) and checks if there any returned values. If there are
;;; none, runs (F A2 B2 ...), and so on.
;;;
;;; If any of the lists end, then ANY-VALUES returns no values.
(define (any-values f . lists)
(after ((when (not (null? lists)))
(when (all pair? lists)))
(let-values ((returned (apply f (map car lists))))
(if (null? returned)
(apply any-values f (map cdr lists))
(apply values returned)))))

167
units.scm Normal file
View File

@ -0,0 +1,167 @@
;;; Copyright 2024 Peter McGoron
;;; Licensed under the Apache License, Version 2.0 (the "License");
;;; you may not use this file except in compliance with the License.
;;; You may obtain a copy of the License at
;;;
;;; http://www.apache.org/licenses/LICENSE-2.0
;;;
;;; Unless required by applicable law or agreed to in writing, software
;;; distributed under the License is distributed on an "AS IS" BASIS,
;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
;;; implied. See the License for the specific language governing
;;; permissions and limitations under the License.
;;;
;;; Example of COND-VALUES using units.
(load "cond-values.scm")
(define *si-prefixes*
'((quetta . #e1e30)
(ronna . #e1e27)
(yotta . #e1e24)
(zetta . #e1e21)
(exa . #e1e18)
(peta . #e1e15)
(tera . #e1e12)
(giga . #e1e9)
(mega . #e1e6)
(kilo . #e1e3)
(hecto . #e1e2)
(deka . #e1e1)
(deci . #e1e-1)
(centi . #e1e-2)
(milli . #e1e-3)
(micro . #e1e-6)
(nano . #e1e-9)
(pico . #e1e-12)
(femto . #e1e-15)
(atto . #e1e-18)
(zepto . #e1e-21)
(yocto . #e1e-24)
(ronto . #e1e-27)
(quecto . #e1e-30)))
(define *si-algebra*
`((/ . ,/)
(* . ,*)))
(define (atom-d unit)
(after ((when (or (symbol? unit)
(and (number? unit) (exact? unit)))))
unit))
(define (prefixed-d unit)
(after ((let (length* unit 2) => (head unit))
(let (assq-d head *si-prefixes*) => (factor)))
(values factor unit)))
(define (power-d unit)
(after ((let (length* unit 3) => (head number unit))
(when (eq? head '^)))
(values number unit)))
(define (algebra-function-d unit)
(after ((let (length-at-least unit 3) => (head . rest))
(let (assq-d head *si-algebra*) => (procedure)))
(values head procedure rest)))
(define (remove-prefixes unit)
(cond-values
(after ((let (atom-d unit) => (unit)))
(values 1 unit))
;;
(after ((let (prefixed-d unit) => (factor unit)))
(let-values (((sub-factor unit-w/o-factors)
(remove-prefixes unit)))
(values (* sub-factor factor) unit-w/o-factors)))
;;
(after ((let (power-d unit) => (power unit)))
(let-values (((sub-factor sub-unit)
(remove-prefixes unit)))
(values (expt sub-factor power)
(list '^ power sub-unit))))
;;
(after ((let (algebra-function-d unit) => (head proc units)))
(let-values (((factors units)
(map-values remove-prefixes units)))
(values (apply proc factors)
(cons head units))))
(else (error "invalid unit" unit))))
(remove-prefixes '(/ (* (centi meter) (centi meter))
volt
second))
(remove-prefixes '(/ (^ 2 (centi meter))
volt
second))
(define (make-unit-destructor atom prefixed power algebra-function on-else)
(lambda (unit)
(cond-values
(apply-after (atom-d unit) atom)
(apply-after (prefixed-d unit) prefixed)
(apply-after (power-d unit) power)
(apply-after (algebra-function-d unit) algebra-function)
(else (on-else unit)))))
(import r7rs)
(define (remove-prefixes unit)
(define (on-atom unit)
(values 1 unit))
(define (on-prefixed prefix-factor unit)
(let-values (((sub-prefix sub-unit) (remove-prefixes unit)))
(values (* prefix-factor sub-prefix) sub-unit)))
(define (on-power power unit)
(let-values (((sub-prefix sub-unit) (remove-prefixes unit)))
(values (expt sub-prefix power) sub-unit)))
(define (on-algebra-function symbol procedure units)
(let-values (((prefixes units) (map-values remove-prefixes units)))
(values (apply procedure prefixes)
(cons symbol units))))
(define (on-else unit)
(error "invalid unit" 'remove-prefixes unit))
(define remove-prefixes
(make-unit-destructor on-atom
on-prefixed
on-power
on-algebra-function))
(remove-prefixes unit))
(define remove-prefixes-destructors '())
(define remove-prefixes-handlers '())
(define (add-remove-prefixes-handler destructor handler)
(set! remove-prefixes-destructors
(cons destructor remove-prefixes-destructors))
(set! remove-prefixes-handlers
(cons handler remove-prefixes-handlers)))
(define (remove-prefixes unit)
(cond-values
(any-values (lambda (destructor handler)
(apply-after (destructor unit) handler))
remove-prefixes-destructors
remove-prefixes-handlers)
(else (error "invalid unit" unit))))
(add-remove-prefixes-handler atom-d (lambda (unit)
(values 1 unit)))
(remove-prefixes 'gram)
(remove-prefixes '(kilo gram))
(add-remove-prefixes-handler prefixed-d
(lambda (factor unit)
(let-values (((sub-factor sub-unit)
(remove-prefixes unit)))
(values (* factor sub-factor) sub-unit))))
(add-remove-prefixes-handler
algebra-function-d
(lambda (head procedure units)
(let-values (((factors units) (map-values remove-prefixes units)))
(values (apply procedure factors)
(cons head units)))))
(remove-prefixes '(/ (kilo meter) (micro second)))

66
units.sml Normal file
View File

@ -0,0 +1,66 @@
datatype si_prefix
= QUETTA | RONNA | YOTTA | ZETTA | EXA | PETA | TERA | GIGA | MEGA
| KILO | HECTO | DEKA | DECI | CENTI | MILLI | MICRO | NANO
| PICO | FEMTO | ATTO | ZEPTO | YOCTO | RONTO | QUECTO;
datatype si_function
= DIVISION | MULT;
datatype si_unit
= UNIT of string
| PREFIX of si_prefix * si_unit
| ALGEBRA of si_function * si_unit list
;
fun factor_of_prefix QUETTA = 1e30
| factor_of_prefix RONNA = 1e27
| factor_of_prefix YOTTA = 1e24
| factor_of_prefix ZETTA = 1e21
| factor_of_prefix EXA = 1e18
| factor_of_prefix PETA = 1e15
| factor_of_prefix TERA = 1e12
| factor_of_prefix GIGA = 1e9
| factor_of_prefix MEGA = 1e6
| factor_of_prefix KILO = 1e3
| factor_of_prefix HECTO = 1e2
| factor_of_prefix DEKA = 1e1
| factor_of_prefix DECI = 1e~1
| factor_of_prefix CENTI = 1e~2
| factor_of_prefix MILLI = 1e~3
| factor_of_prefix MICRO = 1e~6
| factor_of_prefix NANO = 1e~9
| factor_of_prefix PICO = 1e~12
| factor_of_prefix FEMTO = 1e~15
| factor_of_prefix ATTO = 1e~18
| factor_of_prefix ZEPTO = 1e~21
| factor_of_prefix YOCTO = 1e~24
| factor_of_prefix RONTO = 1e~27
| factor_of_prefix QUECTO = 1e~30
;
fun apply_function DIVISION (head::[]) = head
| apply_function DIVISION [] = raise Match
| apply_function DIVISION (x::y::rest)
= apply_function DIVISION (x/y::rest)
| apply_function MULT [] = 1.0
| apply_function MULT (head::[]) = head
| apply_function MULT (x::y::rest)
= apply_function MULT (x*y::rest)
;
fun car (x,y) = x;
fun cdr (x,y) = y;
fun remove_prefixes (UNIT x) = (1e0, UNIT x)
| remove_prefixes (PREFIX (prefix, the_unit))
= let val (factor, sub_unit) = remove_prefixes the_unit
in (factor * (factor_of_prefix prefix), sub_unit)
end
| remove_prefixes (ALGEBRA (function, units))
= let val returned = map remove_prefixes units;
val factors = map car returned;
val units = map cdr returned;
in
(apply_function function factors, (ALGEBRA (function, units)))
end
;